The length reduction of rod antennas is nowadays a major concern in the automotive industry. The need for new shorter rods stems from the desire to fulfil the design aesthetics of modern cars and to alleviate the mechanical issues the longer rods have. However, despite the severe length reduction, the short rods have to perform at least as good as the 40 cm long active monopoles usually met nowadays. In this context, the present thesis investigates the possibilities to use for AM, FM and DAB broadcast reception in an automotive environment 20 cm long active monopole antennas and 14 cm long active helical elements. Electrically very short active antennas are challenging because the very low effective height of the antenna element and its inconvenient antenna impedance with a highly reactive character pose important constrains upon the antenna amplifier. The amplifier has to have high input impedance, which has to be increasingly higher, as the antenna impedance gets also higher. At the same time, the amplifier has to exhibit enough gain and low noise character, in order to achieve good sensitivity. There are also important requirements to be fulfilled concerning its linearity.     «

The length reduction of rod antennas is nowadays a major concern in the automotive industry. The need for new shorter rods stems from the desire to fulfil the design aesthetics of modern cars and to alleviate the mechanical issues the longer rods have. However, despite the severe length reduction, the short rods have to perform at least as good as the 40 cm long active monopoles usually met nowadays. In this context, the present thesis investigates the possibilities to use for AM, FM and DAB bro...    »